Conventional datacenters include a complex mesh of N-tier applications. Each tier typically includes multiple servers (nodes) that are dedicated to each application or application portion. These nodes generally include one or more computer systems that execute an application or portion thereof, and provide computing resources to clients. Some systems are general purpose computers (e.g., a Pentium-based server system) having general purpose operating systems (e.g., Microsoft Server 2003) while others are special-purpose systems (e.g., a network attached storage system, database server, etc.) that is specially developed for this purpose using custom operating system(s) and hardware. Typically, these servers provide a single function (e.g., file server, application server, backup server, etc.) to one or more client computers coupled through a communication network (e.g., enterprise network, Internet, combination of both).
Configurations of datacenter resources may be adjusted from time to time depending on the changing requirements of the applications used, performance issues, reallocation of resources, and other reasons. Configuration changes are performed, for example, by manually reconfiguring servers, adding memory/storage, etc., and these changes generally involve a reboot of affected computer systems and/or an interruption in the execution of the affected application. There exist other techniques such as server farms with front-end load balancers and grid-aware applications that allow the addition and deletion of resources, however, the operating systems or applications on which they are supported must be specifically developed to operate in such an environment.